Planer-knife



(No Modell.)

E.' BENJAMIN.

PLANBR KNIFE. u. No. 293,135 y Patented Feb; 5,1884` i @MMM IoA cle.

` rares PATENT `rrrca EDVIN BEXJAllIIN, OF SOUTH EVANSTON, ILLINOIS.

PL-ANER-KNIFE.

SPECIFICATION forming part of Letters Patent No, 293,135, dated February 5, 1584. Application filell April 1G, 1883. (Xo model.)

To ctZZ, wlw/zt t nul/y concern: i

Be itknown that I, EDWIN BENJAMIN, a citizen of the United States, residing at South Evanston, in the county of Cook and State of Illinois, have invented a certainV new and useful Improvement in Planer-Knives, of which the following is a'full, clear, concise, and eX- act description, reference being had tothe accompanying drawings, forming a part of this specification.

My invention consists in a planer-knife in which that portion ofthe knife which is next to the cutting-edge is lightened byreducing the quantity of metal therein, whereby the centrifugal force is more evenly distributed over the different portions of the knife when it is being revolved by the cylinder to whichit is attached.

Planer-knives, when revolved on a cylinder in the usual manner, necessarily travel faster at the cutting-edge than at the heel or at any other part of the'knife, because the cuttingedge must project beyond the other portions of the knife or cylinder, Vin order to do the cutting, and therefore travels in a greater cirrIhis difference in velocity between the front and rear portions of the knife on highspeed cylinders amounts in some cases to over a thousand feet per minute. The knives are usually bolted to the cylinder near their centers, so that the weight of each knife is distributed on each side of its fastening-bolts, with usually a preponderance of weight on the side next to the cutting-edge. rlhe front portion of the knife travelingat the greater velocity, its momentum will be much greater than that of the rear portion. The centrifugal force, acting on the front or cutting portion, is therefore much greater than that acting upon the heel of the knife. The consequence is a tendency of the front portion of the knife to throw awayfrom the cylinder. In my iml proved knife I have sought to overcome this difficulty by decreasing the weight of the front portionof the knife, and thereby decreasing the centrifugal force acting thereupon, thus more evenly distributing the effect of the centrifugal force over the different portions of the knife.

In the accompanying drawings, Figure 1 is a view of a knife embodying my invention, shown attached to a cylinder in the ordinary manner, the different paths in which the front and rear portions of the knife travel being indicatedby dotted lines. Fig. 2 is a plan view of the knife detached. Fig. 3 is a transverse sectional View of the same, taken on line a: x; and Fig. 4 is a partial longitudinal sectional view on line y y.

In the said drawings, A represents the knife 5 B, the cylinder, to which it is secured in the ordinary manner by a bolt, C. a a represent the pathpf the cutting edge, and b b that of the heel of the knife.

The manner in which I have shown my invention carried out is by constructing the knife with aseries of transverse flutes, s, which extend from near the center of the knife to the cutting-edge. By this construction I am enabled to considerably lighten this portion of the knife and at the same time retain the requisite amount of strength and stiffness. The flutes may be of any desired shape or size to attain the desired result. I do not, therefore, limit myself to any particular shape or num ber. l

The knife may be provided with the ordinary slots, t, through which the bolts pass in securing it to the cylinder; or :it may be se cured in any other suitable manner.

A knife constructed with the flutes as above set forth is much easier ground than a plain knife of the ordinarytypc, there being less stock to grind awa-y.

Having thus described my claiml. A planer-knife adapted to be secured by fastening-bolts at or near its center to a revolving cylinder, said knife having that portion which extends forward from the fasten` ing-bolts to the cutting-edge lightened, substantially as described, whereby the momen tum of the forward portion of the knife is rcduced. l

2. A planer-knife adapted to bc secured at o r near its center to a revolving cylinder,` said knife being provided with a series of transverse flutes extending from near the een invention, I

substantially as described.

ter of the knife toward the cutting edge, In witness whereof I hereunto subscribe my io whereby said knife is lightened, substantially 11a-nie this 9th day of April, A. D. 18S3. as and for the purpose specified. l

3. The eombinationn a planer-knife adapted to be bolted to zn revolving cylinder7 of the slots t, through which the fastening-bolts pass, and the transverse flutes extending from near the center ofthe knife' toward the eutt-i 11g-edge,

EDW'IN BENJAMIN.

lVitnesses:

DANL. H. PATRICK, PAUL A. STALEY. 

